1. Field of the Invention
The present invention relates to a light source device that has: a light-emitting tube including a light-emitting portion that generates a light beam by an electric discharge between electrodes, and sealing portions provided on both sides of the light-emitting portion; and a reflector including a neck portion provided with an insertion hole to which the light-emitting tube is inserted, and a reflecting portion integrally formed with the neck portion and having an ellipsoidal curved reflecting surface that irradiates the light beam emitted by the light-emitting portion forward after and aligns the light beam in a predetermined direction, as well as to a projector including the light source device.
2. Description of Related Art
Conventionally, projectors that modulate a light beam irradiated by a light source in accordance with image information to project an optical image in an enlarged manner have been used for the purpose of presentation at conferences etc in conjunction with personal computers. Besides, such projectors are recently used for the purpose of home-theater for serving the needs of watching movies etc. on a wide screen at home.
The known light source device used for the projector is that houses an electric discharge light-emitting tube such as a metal halide lamp or high-pressure mercury lamp and a reflector in a lamp housing etc. by integrating each other.
The light-emitting tube, or a high-pressure mercury lamp for instance, has a light-emitting portion in which a pair of tungsten electrodes spaced apart by a predetermined distance, mercury, rare gas and a small amount of halogen are sealed, and sealing portions provided on both sides of the light-emitting portion with molybdenum foils electrically connected to the electrodes inserted and sealed by glass material etc.
The reflector has a neck portion with an insertion hole to which the light-emitting tube is inserted, and a reflecting portion integrally formed with the neck portion and having an ellipsoidal curved reflecting surface that irradiates the light beam emitted by the light-emitting portion and aligns the light beam in a predetermined direction.
When the light-emitting tube and the reflector are integrated, the sealing portion of the light-emitting tube is inserted to the insertion hole of the reflector, positioned so that the light-emitting portion is positioned at a predetermined position inside the reflector, and consequently the light-emitting tube can be fixed inside the reflector by curing a silica-alumina inorganic adhesive after filling it from the base end side of the insertion hole to the part between the insertion hole and the sealing portion.
Note that, it would be difficult to fill the inorganic adhesive if the gap between the insertion hole and the sealing portion is too small whereas the inorganic adhesive would overflow from the gap to the reflecting surface of the reflector if the gap is too large.
Therefore, such configuration is conventionally suggested that a narrow part is formed on the insertion hole of the reflector at a part adjacent to the reflecting surface, so that the inorganic adhesive does not overflow to the reflecting surface (see JP2002-62586A, JP6-203806A).
However, in the above prior arts according to the references, deposition processing on the reflecting surface is conducted from the side of the reflecting portion of the reflector when the reflecting surface of the reflector being deposited, and consequently, the material for forming the reflecting surface is also formed on the edge of the opening of the insertion hole. Accordingly, when injecting and filling the adhesive, the adhesive may adhere on the reflection film formed on the edge of the opening of the insertion hole, thus corroding the reflecting surface.
An object of the present invention is to provide a light source device that inhibits the corrosion on a reflecting surface of the reflector due to an inorganic adhesive used for fixing a light-emitting tube on the reflector, as well as a projector.